Vertebral body and disc space replacement devices

ABSTRACT

A vertebral replacement body device for supporting adjacent vertebrae includes a connecting member having an upper member and a lower member engaged thereto at opposite ends thereof. The vertebral replacement body device can have a chamber extending therethrough for fusion of the supported vertebrae.

BACKGROUND

[0001] The present invention is directed to devices for replacement ofone or more vertebral bodies and/or one or more disc spaces betweenvertebrae of a spinal column.

[0002] The repair and reconstruction of bony structures is sometimesaccomplished by directly fixing adjacent bony structures to each other,such as by a plate. In other instances, bone growth inducing materialcan be introduced between the adjacent bony structures, which over timeresults in a solid bony connection. In some instances, the adjacent bonystructures are not sufficiently strong to maintain their patency as thebone heals or the bone grows between the adjacent structures through thebone growth inducing material. In these instances, mesh structures orcages have been provided to engage the adjacent bony structures toprovide additional stability. The cages are generally hollow and can beconfigured to contact the harder cortical bone of the adjacent bonystructures. The hollow portion of the cages can be filled with bonegrowth inducing material.

[0003] Devices have also been provided to replace a removed vertebralbody and to provide a support structure between the remaining vertebraeon either side of the one or more removed vertebral bodies. One exampleof such a device is provided in U.S. Pat. No. 5,192,327.

[0004] The '327 patent describes oval or hemi-oval rings which can beused in isolation in a disc space or stacked one upon another ininterdigitating fashion for replacement of a vertebral body. The ringshave ridges along their top and bottom faces that form peaks and valleysto allow the stacked rings to interdigitate when stacked. One problemwith these interdigitating ridges is that the stack of rings can sliderelative to one another in the direction of the ridges when stacked. The'327 patent also discloses a connecting bar extending through thestacked rings transversely to the ridges to prevent relative slidingbetween the stacked rings. In order to use the connecting bar insurgery, the surgeon must be provided with a multitude of bars ofdiffering heights and/or “custom fit” the bar as needed for the heightof the particular set of stacked cages. In addition, the stacked cagescan separate longitudinally even when the connecting bar extends throughthe stacked cages.

[0005] While prior devices are a step in the right direction, thereremains a need for improved devices for replacing one or more vertebralbodies and/or one or more disc spaces in a spinal column. The presentinvention is directed to satisfying these needs, among others.

DESCRIPTION OF THE FIGURES

[0006]FIG. 1 is a perspective view of a vertebral replacement bodydevice according to one embodiment of the present invention.

[0007]FIG. 2 is an exploded perspective view of the vertebralreplacement body device of FIG. 1.

[0008]FIG. 3 is a side elevation view of the vertebral replacement bodydevice of FIG. 1 in partial section to illustrate the interconnectionbetween end members and a connecting member of the device.

[0009]FIG. 4 is an elevational view of an engaging member comprising aportion of the connecting member of the device of FIG. 1.

[0010]FIG. 5 is an end view of the vertebral replacement body device ofFIG. 1.

[0011]FIG. 6 is a perspective view of an end member comprising a portionof the vertebral replacement body device of FIG. 1.

[0012]FIG. 7 is an elevation view of the end member of FIG. 6.

[0013]FIG. 8 is an elevational view of the vertebral replacement bodydevice of FIG. 1 positioned in the spinal column between two vertebrae.

[0014]FIG. 9 is an elevational view of one of the end members comprisinga portion of the vertebral replacement body device of FIG. 1 positionedin a spinal disc space between adjacent vertebrae.

[0015]FIG. 10 is a perspective view of another embodiment vertebralreplacement body device.

[0016]FIG. 11 is an exploded perspective view of another embodimentvertebral replacement body device.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0017] For the purpose of promoting an understanding of the principlesof the invention, reference will now be made to the illustratedembodiments thereof and specific language will be used to describe thesame. It will nevertheless be understood that no limitation of the scopeof the invention is thereby intended. Any such alterations and furthermodifications in the invention, and any such further applications of theprinciples of the invention as described herein are contemplated aswould normally occur to one skilled in the art to which the inventionrelates.

[0018] The present invention relates to devices for replacing one ormore vertebral bodies in the spinal column and/or one or more discspaces between adjacent vertebrae. It is contemplated that the vertebralreplacement body device will support adjacent ones of the intactvertebrae during fusion thereof. It is further contemplated that one ormore components of the vertebral replacement body device can bepositioned in a disc space between adjacent vertebrae for supporting theadjacent vertebrae during fusion thereof.

[0019] The device can employ current mesh or cage-type devices forengagement with adjacent bony structures, although other types of bonesupporting devices are also contemplated. The vertebral replacement bodydevice can have a tubular form with a hollow chamber extendingtherethrough. The adjacent vertebrae are supported by opposite ends ofthe device and the chamber can be filled with bone growth inducing orosteogenetic material. The ends of the device include flattenedplateau-like end surfaces that can be formed at the junction betweenbars defining the mesh wall structure of the device.

[0020] The vertebral replacement body device includes a middle orconnecting member and at least one of an upper member attached to anupper end of the connecting member and/or a lower member attached to alower end of the connecting member. Each of the upper member, the lowermember and the connecting member can have a generally kidney beancross-sectional shape in the plane transverse to the central axis of theassembled device. Other cross-sectional shapes are also contemplated,including circular, racetrack-shaped, rectangular, square, oval,D-shaped, triangular, or other polygonal shape. Each of the upper memberand the lower member can include an interior chamber. The connectingmember can also include an interior chamber that generally aligns withthe interior chambers of the upper and lower members engaged thereto.

[0021] The upper and lower members can be fabricated from a tubular meshhaving apertures through its wall. One example of a tubular mesh isprovided in U.S. Pat. No. 5,897,556, which is incorporated herein byreference in its entirety. The connecting member can also be fabricatedfrom a tubular mesh. Further forms contemplate that the upper and lowermembers and the connecting member can be a tubular body with solidwalls.

[0022] The upper and lower members can be telescopically andnon-rotatably engaged with the connecting member. In one embodiment, theconnecting member includes an upper extension and a lower extensionextending therefrom. The upper and lower extensions are in the form ofsubstantially continuous rings extending around the respective ends ofthe connecting member. Other forms for the upper and lower extensionsare also contemplated. The upper and lower extensions are received inthe interior chamber of the respective upper or lower member when theupper and lower members are engaged to the connecting member. In anotherembodiment, extensions are provided on the upper and lower members, andthese extensions are received in an interior chamber or opening atrespective ends of the connecting member.

[0023] Each of the upper and lower extensions, and each of the chambersof the upper and lower members, can have a non-circular cross-sectionand interface to prevent relative rotation between the connecting memberand the upper or lower member engaged thereto.

[0024] The upper and lower extensions of the connecting member eachinclude an engaging member which can be flexed inwardly as therespective upper or lower member is placed around the respectiveextension of the connecting member. The engaging member fits into anopening or aperture in the inner wall surface of the respective upperand lower member to axially secure the respective upper and lowermembers to the connecting member.

[0025] The vertebral replacement body device can be made from anybiocompatible material, including synthetic or natural autograft,allograft or xenograft tissues, and can be resorbable or non-resorbablein nature. Examples of tissue materials include hard tissues, connectivetissues, demineralized bone matrix and combinations thereof. Furtherexamples of resorbable materials are polylactide, polyglycolide,tyrosine-derived polycarbonate, polyanhydride, polyorthoester,polyphosphazene, calcium phosphate, hydroxyapatite, bioactive glass, andcombinations thereof. Further examples of non-resorbable materials arenon-reinforced polymers, carbon-reinforced polymer composites, PEEK andPEEK composites, shape-memory alloys, titanium, titanium alloys, cobaltchrome alloys, stainless steel, ceramics and combinations thereof andothers as well.

[0026] Any suitable osteogenetic material or composition is contemplatedfor placement within the chambers defined by the upper member, the lowermember and the connecting member. Such osteogenic material includes, forexample, autograft, allograft, xenograft, demineralized bone, syntheticand natural bone graft substitutes, such as bioceramics and polymers,and osteoinductive factors. Where bony material is placed within thechambers of the components of the vertebral replacement body device, thematerial can be pre-packed into the hollow chambers before the device isimplanted, or can be pushed through the plurality of wall openings afterthe device is in position in the spinal column. A separate carrier tohold the materials within the chambers of the device can also be used.These carriers can include collagen-based carriers, bioceramicmaterials, such as BIOGLASS®, hydroxyapatite and calcium phosphatecompositions. The carrier material can be provided in the form of asponge, a block, folded sheet, putty, paste, graft material or othersuitable form. Moreover, the osteogenetic compositions contained withinthe vertebral replacement body device can comprise an effective amountof a bone morphogenetic protein, transforming growth factor β1,insulin-like growth factor 1, platelet-derived growth factor, fibroblastgrowth factor, LIM mineralization protein (LMP), and combinationsthereof or other therapeutic or infection resistant agent, held within asuitable carrier material.

[0027] In FIGS. 1-2, a vertebral replacement body device 10 includes amiddle or connecting member 12, an upper member 30, and a lower member40. Device 10 is illustrated as having a tubular form that extends alonga longitudinal axis L and defines a chamber extending therethrough alongaxis L. Bone growth can occur through this chamber for fusion betweenthe vertebral bodies supported at each end of device 10.

[0028] Connecting member 12 includes a body 14 extending between anupper end 14 a and an opposite lower end 14 b. Connecting member 12further includes an upper extension 18 a and a lower extension 18 b.Connecting member 12 has an inner wall surface 12 a (FIG. 5) thatdefines a chamber 16 extending between and opening at the outer ends ofthe extensions 18 a, 18 b. Each of the extensions 18 a, 18 b extendsoutwardly from the respective end 14 a, 14 b of body 14 and aroundchamber 16. End surface 15 a extends around upper extension 18 a, andend surface 15 b extends around lower extension 18 b. In the illustratedembodiment, extensions 18 a, 18 b are substantially continuous ringsextending from their respective end 14 a, 14 b. Other embodimentscontemplate other forms for the extensions, such as, for example, aseries of two or more flexible engaging members (such as engaging member20 discussed below) or rigid engaging members.

[0029] The wall of body 14 includes a number of triangular apertures 22which extend through the wall and communicate with chamber 16. Othershapes for apertures 22 are also contemplated, including non-circularshapes such as a square, diamond, oval and/or rectangular shapes,circular shapes, and/or polygonal shapes. The wall of body 14 alsoincludes a number of holes 24 extending at least partially therethrough.Holes 24 can be threaded or otherwise sized and/or configured forengagement with one or more insertion instruments (not shown.)

[0030] Referring further to FIGS. 3-5, the substantially continuous wallof each of the extensions 18 a, 18 b is interrupted by an engagingmember 20. Only engaging member 20 for upper extension 18 a isillustrated, it being understood that lower extension 18 b can also beprovided with an identical or similar engaging member. Engaging members20 secure upper member 30 and lower member 40 to respective ends ofconnecting member 12, resisting axial dislocation of upper member 30 andlower member 40 away from connecting member 12 along axis L. Engagingmembers 20 can also resist axial rotation of upper and lower members 30,40 relative to connecting member 12 about axis L. Other embodimentscontemplate that more than one engaging member 20 is provided in thewall of one or both of the extensions 18 a, 18 b. Further embodimentscontemplate that wall of one or both of the extensions 18 a, 18 b is notsubstantially continuous, but rather is continuous or includes a numberof discrete wall portions sufficiently spaced and sized about body 14 ofconnecting member 12 for engagement with upper and lower members 30, 40.

[0031] Engaging member 20 includes a projection or engaging portion 20 band a stem 20 a connected or integrally formed with end surface 15 a ofbody 14. Stem 20 a has a reduced thickness to allow engaging member 20to deflect inwardly in response to a force applied to engaging portion20 b. Engaging portion 20 b projects outwardly from stem 20 a and has atriangular shape tapering from an engaging surface 20 c to an upper end20 d. Other configurations for engaging member 20 are also contemplated.For example, engaging member 20 can be provided with an engaging portion20 b in the form of a partially spherical or rounded nub, a receptacle,rectangular or polygonal shaped tab or projection. Engaging portion 20 bcan also correspond to the shape the aperture 22 in which it isreceived. Engaging member 20 can also be a snap ring, collet, bayonetlock, or surface irregularity that resists axial movement of the engagedupper member 30 and lower member 40 away from connecting member 12 alongaxis L.

[0032] Referring also to FIGS. 6-7, upper and lower members 30, 40 areillustrated as being identical, although it is also contemplated thatupper member 30 and lower member 40 can be provided with differentconfigurations and/or sizes. With respect to FIGS. 6 and 7, only uppermember 30 will be further described, it being understood that lowermember 40 can be provided with identical features.

[0033] Upper member 30 includes a body 32 extending between an upper end32 a and a lower end 32 b. Body 32 has a height H2 between the upper andlower ends 32 a, 32 b. Height H2 can be selected so that upper member 30fits within an intervertebral disc space between adjacent vertebrae.Upper end 32 a and lower end 32 b can be sloped to converge toward oneanother and form a height H2′ opposite height H2. The sloped ends 32 a,32 b allow upper member 30 to restore and/or conform to the naturalinclination between the adjacent endplates of the vertebral bodies. Itis further contemplated that ends 32 a, 32 b can be parallel to oneanother.

[0034] Body 32 has an inner wall surface 32 c defining a chamber 34 thatextends between and opens at ends 32 a, 32 b. As shown in FIG. 5, body32 has an outer surface 32 d that defines a kidney-shaped cross sectiontransverse to longitudinal axis L. Other cross-sectional shapes are alsocontemplated, including, for example, circular cross-sections andnon-circular cross-sections, such as oval, triangular, square,rectangular, polygonal, boomerang shaped, D-shaped, or racetrack shapedcross-sections. In the illustrated embodiment, connecting member 12 hasthe same cross-sectional shape as the upper and lower members 30, 40 toprovide a vertebral replacement body device of uniform cross-sectionalshape and size along its height.

[0035] Body 32 defines a number of triangular apertures 36 extending atleast partially therethrough in communication with chamber 34, and anumber of circular holes 38 extending at least partially therethroughfrom the exterior surface of body 32. Holes 38 or the other holes can bethreaded or otherwise sized and/or configured for engagement with one ormore insertion instruments.

[0036] Body 32 further includes a number of bearing surfaces 32 e spacedaround first end 32 a and bearing surfaces 32 f spaced around second end32 b. Adjacent ones of each of the bearing surfaces 32 e are separatedfrom one another by V-shaped recesses 32 g. Adjacent ones of each of thebearing surfaces 32 f are separated from one another by V-shapedrecesses 32 h. Bearing surfaces 32 e, 32 f are planar and provide anumber of plateau-like, generally flat bearing surfaces spaced about therespective end of body 32. Bearing surfaces 32 e, 32 f have atrapezoidal shape in the illustrated embodiment, although other shapesare also contemplated. In the illustrated embodiment, ten such bearingsurfaces 32 e, 32 f are provided at each end of body 32. It is alsocontemplated that fewer than ten or more than ten bearing surfaces couldbe provided. It is further contemplated that each end of body 32 couldbe provided with a single, continuous bearing surface extending aroundchamber 34.

[0037] The plateau-like bearing surfaces 32 e, 32 f provide a surfacearea about the ends of body 32 for bearing support of the adjacentvertebral endplate and to resist subsidence of body 32 into thevertebrae. The plateau-like bearing surfaces 32 e, 32 f provide surfacearea contact between the end of body 32 and the adjacent endplate,providing frictional resistance to body 32 sliding or twisting relativeto the adjacent vertebral endplate.

[0038] Upper member 30 and lower member 40 are connected to respectiveends of connecting member 12 to provide vertebral replacement bodydevice 10. Upper member 30 is advanced over upper extension 18 a so thatupper extension 18 a extends into chamber 34. Engaging member 20 flexesinwardly as inner wall surface 32 c of body 32 passes along engagingportion 20 b. Engaging portion 20 b is configured to reside within oneof the apertures 36 extending into the wall of body 32 from chamber 34.When engaging portion 20 b and the respective aperture 36 are aligned,engaging member 20 returns towards its pre-insertion position withengaging portion 20 b residing in the respective aperture 36. Thisengages upper member 30 to connecting member 12, resisting movement ofupper member 30 away from connecting member 12 along axis L. It isfurther contemplated engaging surface 20 c engages the adjacent lowersurface of the respective aperture 36 to provide a positive seat betweenbearing surface 15 a of connecting member 12 and bearing surfaces 32 fabout end 32 b of upper member 30. Lower member 40 is secured to lowerextension 18 b in a similar manner.

[0039] Bearing surfaces 32 f at lower end 32 b of upper member 30 bearagainst end surface 15 a extending about upper extension 18 a ofconnecting member 12. This bearing relationship transmits the spinalcolumn load from upper member 30 to connecting member 12. The bearingsurfaces of the lower member 40 similarly bear against end surface 15 bextending about lower extension 18 b of connecting member 12. The endsurfaces 15 a, 15 b at the ends of body 14 and the adjacent bearingsurfaces of the upper and lower members 30, 40 do not interdigitate.This bearing relationship eliminates stress concentrations and shiftingof the components of device 10 that might result from improperly alignedinterdigitating surfaces.

[0040] Axial rotation of upper member 30 and lower member 40 relative toconnecting member 12 is resisted by the interface between upper andlower extensions 18 a, 18 b and the respective inner wall surface of theupper and lower members 30, 40. In the illustrated embodiment,extensions 18 a, 18 b have a non-circular shape, such as the kidneyshape shown in FIG. 5. Similarly, the inner wall surface 32 c of uppermember 30 and also the inner wall surface of lower member 40 have anon-circular shape sized to receive in form fitting engagement therespective upper or lower extension 18 a, 18 b. This non-circular formfitting engagement prevents rotation of upper member 30 and lower member40 relative to connecting member 12.

[0041] Device 10 can be used to replace a vertebra that has been removedfrom the spinal column segment using known techniques. Device 10 isassembled by securing upper member 30 to one end of connecting member 12and securing lower member 40 to the other end of connecting member 12.This provides a vertebral replacement body device 10 that has an overallheight that is equal to the sum of the heights H1 of body 14, height H2of upper member 30, and height H3 of lower member 40 (FIG. 3.)

[0042] As shown in FIG. 8, the assembly 10 can be placed betweenvertebra VI and vertebra V3 after removal of vertebra V2. Replacement ofmore than one vertebra is also contemplated. Although not required, itis contemplated that height H1 could be representative of that of theremoved vertebra and heights H2, H3 could be representative of theheights of the respective disc spaces between the removed vertebra V2and the remaining vertebrae V1, V3. Also shown in FIG. 8 is astabilization construct 150 engaged to and extending between vertebraeV1 and V3 to support and stabilize the spinal column segment before,during and, if construct 150 is non-resorbable and left in the patient,after fusion. Stabilization construct 150 can be a rod system, platesystem or artificial ligament system. It is further contemplated thatstabilization system could be attached to any portion of vertebrae V1and V3, including the anterior, antero-lateral, lateral, postero-lateralor posterior portions.

[0043] It is also contemplated that heights H2 and H3 could be identicalor different, and that the ends of upper and lower members 30, 40 couldbe provided with the same or differing angles of inclination. It isfurther contemplated that device 10 can comprise a kit having a numberof upper members 30 and lower members 40 of various sizes and heightsH2, H3. A kit could also include a number of connecting members 12 ofvarious sizes and heights H1. Such a kit would provide the surgeonflexibility in selecting the appropriately size and height for membersof a device 10 based on conditions encountered in surgery.

[0044]FIG. 9 illustrates placement of one of the upper or lower members30, 40 in disc space S between adjacent vertebrae V1, V2 to function asan interbody fusion device. Engagement of stabilization construct tovertebrae V1 and V2 is also contemplated.

[0045] It is also contemplated that connecting member 12 could beprovided with one end configured to bear against a vertebral endplate,and that only one of the upper and lower members 30, 40 is engaged tothe other end of connecting member 12. The assembled device could thenbe placed between adjacent vertebrae with an end of connecting member 12and an end of the selected upper or lower member 30, 40 in contact withthe adjacent vertebral endplates.

[0046] In FIG. 10 there is provided an alternate embodiment vertebralreplacement body device 100. Device 100 includes upper member 30 andlower member 40 engaged at opposite ends of a connecting member 12′,which can be similar to connecting member 12 discussed above. Connectingmember 12′ does not include upper and lower extensions extending fromend 14 a′ and 14 b′. To secure upper member 30 and lower member 40 toconnecting member 12′, a sleeve 112 is provided around connecting member12′ that has an upper end 114 a overlapping upper member 30 and a lowerend 114 b overlapping lower member 40.

[0047] Sleeve 112 can be provided with engaging members 117 a, 117 b inthe form of projections, engaging members, tabs or the like on its innerwall surface. Engaging members 117 a, 117 b engage apertures 36, 46 orother receptacle or detent in the outer wall surfaces of upper member 30and lower member 40, respectively. Engaging members could also beprovided to engage apertures 22′ or other receptacle or detent inconnecting member 12′. So engaged, sleeve 112 resists axial movement ofupper member 30 and lower member 40 relative to connecting member 12′.

[0048] It is further contemplated that rotation of upper member 30 andlower member 40 relative to connecting member 12′ could be prevented bya non-circular, telescoping interface between the members such asdiscussed above. In another embodiment, rotation of upper member 30 andlower member 40 relative to connecting member 12′ could be prevented bythe engagement of sleeve 112 with the upper and lower members 30, 40and, if so configured, with connecting member 12′. In yet a further formof the embodiment of FIG. 10, the connecting member 12′ could beintegral with sleeve member 112 to provide upper and lower bearingsurfaces within sleeve 112 for support of upper member 30 and lowermember 40 thereon.

[0049] Referring now to FIG. 11, another embodiment vertebralreplacement body device 210 is shown. Device 210 includes a connectingmember 212 having a body 214 extending between an upper end 214 a and alower end 214 b. Upper end 214 a includes an upper extension 218 ahaving an end surface 215 a therearound. Extension 218 a extends arounda bearing surface 216 at the upper end of chamber 220. Bearing surface216 is positioned below end surface 215 a in chamber 220. Second end 215b similarly includes an extension 218 b having an end surface 215 b, anda bearing surface (not shown) at the lower end of chamber 220 below endsurface 215 b.

[0050] Upper member 230 includes a body 232 having an upper end 232 aand a lower end 232 b. Body 232 extends around a chamber 234. Lowermember 240 includes a body 242 having a lower end 242 a and an upper end242 b. Body 242 extends around a chamber 244. Lower member 240 includesan inset wall 248 extending around chamber 244, and a bearing surface250 extending around body 242 below inset wall 248. Upper member 230similarly includes an inset wall 238 and a bearing surface (not shown)extending around body 232 above inset wall 238.

[0051] When assembled, inset wall 238 of upper member 230 is received inchamber 220 of connecting member 212 with extension 218 a extendingaround inset wall 238. Similarly, inset wall 248 of lower member 240 isreceived in chamber 220 of connecting member 212 with extension 218 bextending around inset wall 248. It contemplated that end surface 215 acan contact the bearing surface extending around inset wall 238, andthat end surface 215 b can contact bearing surface 250 extending aroundinset wall 248. Additionally or alternatively, the lower end of insetwall 238 can contact bearing surface 216 in chamber 220 at the upper endof connecting member 212, and the upper end of inset wall 248 cancontact the bearing surface (not shown) in chamber 220 at the lower endof connecting member 212.

[0052] Connecting member 212 and/or upper and lower members 230, 240could be provided with engaging members or a sleeve such as discussedabove to prevent axial and/or rotational movement of upper and lowermembers 230, 240 relative to connecting member 212 when device 210 isassembled. In a further embodiment, connecting member 212 does notinclude the upper bearing surface 216 and the lower bearing surface inchamber 220 since extensions 218 a, 218 b are not provided on connectingmember 212. In this embodiment, inset walls 238 and 248 are received inchamber 220 at the respective end of connecting member 212, and endsurfaces 215, 215 b contact respective ones of the bearing surfacesextending around inset walls 238, 248.

[0053] While the invention has been illustrated and described in detailin the drawings and foregoing description, the same is to be consideredas illustrative and not restrictive in character, it being understoodthat only the preferred embodiments have been shown and described andthat all changes and modifications that come within the spirit of theinvention are desired to be protected.

What is claimed is:
 1. A vertebral replacement body device, comprising:an upper member having a first end for engaging an endplate of an uppervertebral body and an opposite second end, said upper member defining achamber extending between said first end and said second end; a lowermember having a first end for engaging an endplate of a lower vertebralbody and an opposite second end, said lower member defining a chamberextending between said first end and said second end; and a connectingmember between said upper member and said lower member, said connectingmember including a body having an upper end and a lower end, saidconnecting member further including an upper extension at said upper endof said body and a lower extension at said lower end of said body, saidupper extension being positionable in said chamber of said upper membersuch that said upper member is non-rotatably engaged with saidconnecting member and said lower extension being positionable in saidchamber of said lower member such that said lower member isnon-rotatably engaged with said connecting member.
 2. The device ofclaim 1, wherein said connecting member includes a chamber extendingtherethrough.
 3. The device of claim 2, wherein: said upper extensionincludes a flexible engaging member having a projection engageable withan opening in a wall of said upper member; and said lower extensionincludes a flexible engaging member having a projection engageable withan opening in a wall of said lower member.
 4. The device of claim 2,wherein: said chamber of said upper member and said chamber of saidconnecting member align with one another when said upper member isengaged to said connecting member; and said chamber of said lower memberand said chamber of said connecting member align with one another whensaid lower member is engaged to said connecting member.
 5. The device ofclaim 2, further comprising bone growth material in said chamber of eachof said upper member, said connecting member and said lower member. 6.The device of claim 5, wherein said bone growth material includes one ormore selected from group consisting of: bone morphogenetic protein,transforming growth factor β1, insulin-like growth factor 1,platelet-derived growth factor, fibroblast growth factor, and LIMmineralization protein (LMP).
 7. The device of claim 5, wherein saidbone growth material is provided in a carrier having a form selectedfrom the group consisting of: a sponge, a block, folded sheet, putty,and paste.
 8. The device of claim 1, wherein: said vertebral replacementbody has a longitudinal axis extending therethrough; said upperextension has a non-circular shape transverse to said longitudinal axis;and said lower extension has a non-circular shape transverse to saidlongitudinal axis.
 9. The device of claim 8, wherein: said chamber ofsaid upper member has a non-circular cross-sectional shape transverse tosaid longitudinal axis and said upper extension is received in saidchamber in form fitting engagement with an inner wall surface of saidupper member; and said chamber of said lower member has a non-circularcross-sectional shape transverse to said longitudinal axis and saidlower extension is received in said chamber in form fitting engagementwith an inner wall surface of said lower member.
 10. The device of claim1, wherein: said upper member has a wall extending about said chamber,said wall defining a plurality of openings therethrough communicatingwith said chamber; and said lower member has a wall extending about saidchamber, said wall defining a plurality of openings therethroughcommunicating with said chamber.
 11. The device of claim 10, wherein atleast one of said plurality of openings of each of said upper member andsaid lower member has a triangular shape.
 12. The device of claim 10,wherein said connecting member includes a chamber extending therethroughand said body of said connecting member includes a wall extending aroundsaid chamber, said wall including a plurality of openings therethroughin communication with said chamber of said connecting member.
 13. Thedevice of claim 1, wherein: the vertebral replacement body device has alongitudinal axis extending therethrough; and said upper member, saidlower member and said connecting member each have a kidney shapedcross-section transverse to said longitudinal axis.
 14. The device ofclaim 1, wherein: said first end of said upper member includes a seriesof plateau-like surfaces spaced therearound for bearing against theendplate of the upper vertebral body; and said first end of said lowermember includes a series of plateau-like surfaces spaced therearound forbearing against the endplate of the lower vertebral body.
 15. The deviceof claim 14, wherein said plateau-like surfaces of each of said uppermember and said lower member have a trapezoidal shape.
 16. The device ofclaim 14, wherein said plateau-like surfaces of each of said uppermember and lower member extend generally parallel to an adjacentvertebral endplate.
 17. The device of claim 1, wherein said upper end ofsaid body of said connecting member defines an upper end surfaceextending radially about said upper extension and said lower end of saidbody of said connecting member defines a planar surface extendingradially about said lower extension, said upper extension projectingbeyond said upper end surface and said lower extension projecting beyondsaid lower end surface.
 18. The device of claim 17, wherein: said secondend of said upper member includes a series of plateau-like surfacesspaced therearound for bearing against said upper end surface of saidconnecting member; and said second end of said lower member includes aseries of plateau-like surfaces spaced therearound for bearing againstsaid lower end surface of said connecting member.
 19. The device ofclaim 1, wherein said upper member, said connecting member and saidlower member are comprised of resorbable material selected from thegroup consisting of: hard tissues, connective tissues, demineralizedbone matrix, polylactide, polyglycolide, tyrosine-derived polycarbonate,polyanhydride, polyorthoester, polyphosphazene, calcium phosphate,hydroxyapatite, bioactive glass, and combinations thereof
 20. The deviceof claim 1, wherein said upper member, said connecting member and saidlower member are comprised of non-resorbable material selected from thegroup consisting of: non-reinforced polymers, carbon-reinforced polymercomposites, PEEK, PEEK composites, shape-memory alloys, titanium,titanium alloys, cobalt chrome alloys, stainless steel, ceramics andcombinations thereof.
 21. The device of claim 20, wherein said uppermember, said connecting member and said lower member are each comprisedof PEEK material.
 22. The device of claim 1, further comprising astabilization construct extending between and engaged to the uppervertebral body and the lower vertebral body.
 23. A vertebral replacementbody device, comprising: an upper member having a first end for engagingan endplate of an upper vertebral body and an opposite second end, saidupper member having a wall defining a chamber extending between saidfirst end and said second end; a lower member having a first end forengaging an endplate of a lower vertebral body and an opposite secondend, said lower member having a wall defining a chamber extendingbetween said first end and said second end; and a connecting memberpositionable between said upper member and said lower member, saidconnecting member having a chamber extending therethrough and includinga body having an upper end and a lower end, said connecting memberfurther including an upper extension at said upper end of said body anda lower extension at said lower end of said body, said upper extensionincluding a flexible upper engaging member having a projectionengageable with said wall of said upper member and said lower extensionincluding a flexible lower engaging member having a projectionengageable with said wall of said lower member.
 24. The device of claim23, wherein: said upper extension is positionable in said chamber ofsaid upper member such that said upper member is non-rotatably engagedwith said connecting member; and said lower extension is positionable insaid chamber of said lower member such that said lower member isnon-rotatably engaged with said connecting member.
 25. The device ofclaim 23, wherein said upper extension and said lower extension are eacha substantially continuous ring member interrupted by said respectiveengaging member.
 26. The device of claim 23, wherein: said upper memberincludes at least one aperture extending through said wall of said uppermember; and said lower member includes at least one aperture extendingthrough said wall of said lower member.
 27. The device of claim 26,wherein each of said upper and lower engaging members includes anengaging portion positionable in said at least one aperture ofrespective ones of said upper member and said lower member.
 28. Thedevice of claim 27, wherein each of said upper and lower engagingmembers includes an engaging surface that engages a surface of said atleast one aperture to resist axial displacement of respective ones ofsaid upper member and said lower member relative to said connectingmember.
 29. The device of claim 28, wherein each said at least oneapertures of said upper member and said lower member has a triangularshape and each of said engaging portions has a triangular shape sized tofit within said at least one aperture.
 30. The device of claim 23,wherein each of said upper and lower engaging members flexes inwardlytoward said chamber of said connecting member as respective ones of saidupper member and said lower member are engaged to said connectingmember.
 31. The device of claim 23, wherein said upper engaging memberis integrally formed with said upper end of said body of said connectingmember and said lower engaging member is integrally formed with saidlower end of said body of said connecting member.
 32. The device ofclaim 23, wherein said upper end of said body of said connecting memberdefines an upper end surface extending about said upper extension andsaid lower end of said body of said connecting member defines a lowerend surface extending about said lower extension, said upper extensionprojecting beyond said upper end surface and said lower extensionprojecting beyond said lower end surface.
 33. The device of claim 32,wherein: said second end of said upper member includes a series ofplateau-like surfaces spaced therearound for bearing against said upperend surface of said connecting member; and said second end of said lowermember includes a series of plateau-like surfaces spaced therearound forbearing against said lower end surface of said connecting member.
 34. Avertebral replacement body device, comprising: an upper member having afirst end for engaging an endplate of an upper vertebral body and anopposite second end, said upper member having a wall defining a chamberextending between said first end and said second end; a lower memberhaving a first end for engaging an endplate of a lower vertebral bodyand an opposite second end, said lower member having a wall defining achamber extending between said first end and said second end; aconnecting member positionable between said upper member and said lowermember, said connecting member having a body with an upper end and alower end, said connecting member further including an upper extensionat said upper end of said body and a lower extension at said lower endof said body, wherein: said upper end of said body of said connectingmember includes an upper end surface adjacent to said upper extension;said lower end of said body of said connecting member includes an endsurface adjacent to said lower extension; said second end of said uppermember includes an end surface bearing against said upper end surface ofsaid connecting member; and said second end of said lower memberincludes an end surface bearing against said lower end surface of saidconnecting member.
 35. The device of claim 34, wherein said second endof said upper member includes a series of plateau-like end surfacesspaced therearound; and said second end of said lower member includes aseries of plateau-like surfaces spaced therearound.
 36. The device ofclaim 34, wherein said upper extension includes a flexible upperengaging member having a projection engageable with said wall of saidupper member and said lower extension includes a flexible lower engagingmember having a projection engageable with said wall of said lowermember.
 37. The device of claim 36, wherein said upper engaging memberis integrally formed with said upper end of said body of said connectingmember and said lower engaging member is integrally formed with saidlower end of said body of said connecting member.
 38. The device ofclaim 36, wherein each of said upper and lower engaging members includesan engaging portion forming said projection.
 39. The device of claim 36,wherein each of said upper and lower engaging members includes anengaging surface that engages a surface of at least one aperture in saidwall of each of said upper member and said lower member to resist axialdisplacement of said upper member and said lower member relative to saidconnecting member.
 40. The device of claim 34, wherein said upper memberis telescopically and non-rotabably positionable about said upperextension and said lower member is telescopically and non-rotatablypositionable about said lower extension.
 41. The device of claim 34,wherein said upper member is telescopically and non-rotabablypositionable within said upper extension and said lower member istelescopically and non-rotatably positionable within said lowerextension.
 42. The device of claim 34, further comprising a sleeve aboutsaid connecting member and at least a portion of said upper member andsaid lower member, said sleeve engaging at least said upper member andsaid lower member to maintain said end surfaces of said upper and lowermembers in contact with a respective one of said upper and lower endsurfaces of said connecting member.
 43. A vertebral replacement bodydevice, comprising: an upper member having a first end for engaging anendplate of an upper vertebral body and an opposite second end, saidupper member having a wall defining a chamber extending between saidfirst end and said second end; a lower member having a first end forengaging an endplate of a lower vertebral body and an opposite secondend, said lower member having a wall defining a chamber extendingbetween said first end and said second end; a connecting memberpositionable between said upper member and said lower member, saidconnecting member including a body having a chamber extending between anupper end and a lower end of said body, wherein: said connecting memberand said upper member are telescopically and non-rotatably positionablewith respect to one another for placement of said second end of saidupper member against said upper end of said connecting member; and saidconnecting member and said lower member are telescopically andnon-rotatably positionable with respect to one another to one anotherfor placement of said second end of said lower member against said upperend of said connecting member.
 44. The device of claim 43, wherein saidconnecting member further includes an upper extension at said upper endof said body and a lower extension at said lower end of said body, saidupper extension including a flexible upper engaging member having aprojection engageable with said wall of said upper member and said lowerextension including a flexible lower engaging member having a projectionengageable with said wall of said lower member.
 45. The device of claim44, wherein said upper extension and said lower extension are each asubstantially continuous ring member interrupted by said respectiveengaging member.
 46. The device of claim 44, wherein said upper memberincludes a lower extension at said second end of said lower memberpositionable in said chamber of said connecting member and said lowermember includes an upper extension at said second end of said lowermember positionable in said chamber of said connecting member.
 47. Akit, comprising: a number of members each having a first end and anopposite second for engaging an endplate of a vertebral body, each ofsaid members having a wall defining a chamber extending between saidfirst end and said second end and a height between said first end andsaid second end, wherein at least two of said number of members havedifferent heights between said first and second ends; and at least oneconnecting member having a body extending between an upper end and alower end of said body and a height between said upper end and saidlower end, wherein each of said number of members are telescopically andnon-rotatably engageable to either of said upper end and said lower endof said connecting member.
 48. The kit of claim 47, wherein said firstend and said second end of at least one of said members are slopedrelative to one another.
 49. The kit of claim 47, further comprising astabilization construct attachable to a first vertebral body and asecond vertebral body.
 50. The kit of claim 47, further comprising atleast two connecting members of different height.
 51. A method forassembling a vertebral replacement body device, comprising: providing aconnecting member having a body extending between an upper end and alower end; telescopically and non-rotatably engaging an upper member tothe upper end of the connecting member with an end of the upper memberin contact with the upper end of the body; and telescopically andnon-rotatably engaging a lower member to the lower end of the connectingmember with an end of the lower member in contact with the lower end ofthe body.
 52. The method of claim 51, further comprising: engaging anaperture of the upper member with an engagement member extending fromthe upper end of the body of the connecting member; and engaging anaperture of the lower member with an engagement member extending fromthe lower end of the body of the connecting member.
 53. The method ofclaim 51, further comprising: placing bone growth material in a chamberof said connecting member, a chamber of said upper member, and a chamberof said lower member.
 54. The method of claim 51, wherein the vertebralreplacement body defines a longitudinal axis and non-rotatably engagingthe upper member and the lower member includes providing an interferencefit between the connecting member and respective ones of the uppermember and lower member about the longitudinal axis.
 55. The method ofclaim 51, wherein telescopically engaging the upper member and the lowermember includes positioning a portion of the connecting member in achamber of each the upper member and the lower member.
 56. The method ofclaim 51, wherein telescopically engaging the upper member and the lowermember includes: positioning a portion of the upper member in a chamberof the connecting member; and positioning a portion of the lower memberin a chamber of the connecting member.
 57. The method of claim 51,wherein telescopically and non-rotatably engaging the upper member tothe connecting member and telescopically and non-rotatably engaging thelower member to the connecting member includes placing a sleeve aboutthe upper member, the connecting member and the lower member.